How to tell by looking if a loco is a Dash-8, Dash-9, or AC4400?

[oryan_dunn]

Is there a site on the internet that details the visual differences of these units? I've always like the styling of them, but I cannot tell them apart. I personally really like the newer AC6000, but I can tell those easily by the wrap-around radiator in the rear and the larger size.

Thanks,
Ryan

[M636C]

Obviously I'm feeling brave after Mark declined, but I've spent some time worrying about the same problem!

There was a transition between Dash 8 and Dash 9 with a number of small variations.

One reliable indication is the size of the central air intake at the rear end of the raised section of hood behind the cab. The Dash 8 intake is much longer than that on a Dash 9 or AC 4400 - both of these have a smaller intake because the AC4400 has three dynamic brake fans which takes up space used by the Dash 8 intake. To make parts interchangeable, both Dash 9 and AC4400 used the smaller air intake.

To tell an AC4400, you must be able to see the left side of the unit. The AC power conversion equipment sits in a really big box behind the cab on the left side. Dash 9 unts have a smaller box with the air conditioner (an even smaller box) on top of it. The AC4400 has an air conditioner under the cab floor.

The Dash 8 has conventional trucks, while the Dash9 and AC4400 have the later Hi-Ad trucks with visible coil springs each side of the axle bearings (although there may be some exceptions to this, particularly CSX units with steering trucks)

I hope this helps

Peter

[Anonymous]

For me with the BNSF, which isn't as hard since they have mostly dash 9's, check out the painted model number on the loco. Usually at the front of the locomotive just about the truck painted on in small letters and numbers. I've also seen this on NS units near the side windows. I think UP might even do this too.

[dharmon]

If its a Dash 8, the fireball enveloping the long hood will be large with thick black smoke.

A Dash 9' s fire will be more restricted to the upper portion of the hood and the smoke will be grayer in color.

A 4400 will just have fire shooting straight up from the stack, igniting foilage around it.

[:D]

[Anonymous]

Dash-8 - http://www.railpictures.net/viewphoto.php?id=81317
Dash-9 - http://www.railpictures.net/viewphoto.php?id=79513
AC4400CW - http://www.railpictures.net/viewphoto.php?id=81083
AC4400CW (w/radial trucks) - http://www.railpictures.net/viewphoto.php?id=81338

All Dash-8's use the Dash-8 truck. If you'll notice in the photo they look somewhat similar to the HTC truck found on SD40-2's or SD60's. Also, the radiator "wings" found on Dash-8's are skinnier than those on Dash-9's (although later Dash-8's have thicker "wings").

The Dash-9 and AC4400CW units look very similar except AC4400CW's have a bank of AC inverters on the left side. Although both do use the Hi-Ad truck, the AC4400CW (along with the AC6000CW) also uses GE's radial-steering truck.

That's about all there is. M636C had some good points. It's a whole different ball game when you start getting into different phases, door arrangements, and intake placement/arrangements.

Lastly, here is a site that appears to be accurate: http://www.finnmoller.dk/rail-usa/loco-guide/

[adrianspeeder]

Well, because most will be in the shop, just walk up and read the builders plate. :)

ALCO FOREVER!!!

Ok Ok, I just found it easier to just look up the #s of the locos a certain railroad has. Or buy that diesel spotters guide thingie.

Adrianspeeder

[Anonymous]

The windows on the AC4400 will be shaking like there's no tomorrow.

[oryan_dunn]

Wow, thanks for all the very informative replies. I might just pick up one of those books,as I know I would get my money's worth out of it. I still need to do a little looking of my own, but I have similar questions about the SD 70 and 75 units. If you have some good sites or pictures, I'd appreciate it.
Thanks,
Ryan

[Anonymous]

Actually, the SD70M and SD75M are the same except the SD75M has a large panel on the right side (engineer's side) near the cab entrance door that sticks out. I believe there was only one phase of the SD75M but the SD70M has three distinct phases:

SD70/75M Phase I: http://trainiax.0catch.com/emdsd70-75mdb.gif
SD70M Phase II: http://trainiax.0catch.com/emdsd70mdbph2.gif
SD70M Phase III: http://trainiax.0catch.com/emdsd70mdbph3.gif

You really can't tell by the drawings but Phase II and III have flared radiators, while Phase I does not. Phase III also has a newer type cab. Its a slightly modified version of the standard EMD widecab that you would normally find and an SD60M, for example.